tbf_dl: Update (egprs_)ms_class for already known MS

If SGSN provides us with MS class information upon DL data, let's use it
and set it in an already existing MS object if not yet known.

Also remove all unneeded code passing ms_class to append_data() which
would simply try to (again) set the ms_class.

Change-Id: I4979c9344bffd3ba7657bbab94981d233eab801f
diff --git a/tests/tbf/TbfTest.cpp b/tests/tbf/TbfTest.cpp
index 04e711c..096b071 100644
--- a/tests/tbf/TbfTest.cpp
+++ b/tests/tbf/TbfTest.cpp
@@ -277,8 +277,8 @@
 		llc_data[i] = i%256;
 
 	/* Schedule two LLC frames */
-	dl_tbf->append_data(ms_class, 1000, llc_data, sizeof(llc_data));
-	dl_tbf->append_data(ms_class, 1000, llc_data, sizeof(llc_data));
+	dl_tbf->append_data(1000, llc_data, sizeof(llc_data));
+	dl_tbf->append_data(1000, llc_data, sizeof(llc_data));
 
 
 	/* Send only a few RLC/MAC blocks */
@@ -362,8 +362,8 @@
 	OSMO_ASSERT(dl_tbf->state_is(GPRS_RLCMAC_FLOW));
 
 	/* Schedule two LLC frames */
-	dl_tbf->append_data(ms_class, 1000, llc_data, sizeof(llc_data));
-	dl_tbf->append_data(ms_class, 1000, llc_data, sizeof(llc_data));
+	dl_tbf->append_data(1000, llc_data, sizeof(llc_data));
+	dl_tbf->append_data(1000, llc_data, sizeof(llc_data));
 
 	OSMO_ASSERT(dl_tbf->state_is(GPRS_RLCMAC_FLOW));
 
@@ -2668,7 +2668,7 @@
 	OSMO_ASSERT(dl_tbf->state_is(GPRS_RLCMAC_FLOW));
 
 	/* Schedule a small LLC frame */
-	dl_tbf->append_data(ms_class, 1000, test_data, 10);
+	dl_tbf->append_data(1000, test_data, 10);
 
 	OSMO_ASSERT(dl_tbf->state_is(GPRS_RLCMAC_FLOW));
 
@@ -2678,7 +2678,7 @@
 		request_dl_rlc_block(dl_tbf, &fn);
 
 	/* Schedule a large LLC frame */
-	dl_tbf->append_data(ms_class, 1000, test_data, sizeof(test_data));
+	dl_tbf->append_data(1000, test_data, sizeof(test_data));
 
 	OSMO_ASSERT(dl_tbf->state_is(GPRS_RLCMAC_FLOW));
 
@@ -2726,7 +2726,7 @@
 	 * 2 RLC data blocks. Which are enough to test Header Type 1
 	 * cases
 	 */
-	dl_tbf->append_data(ms_class, 1000, test_data, 100);
+	dl_tbf->append_data(1000, test_data, 100);
 
 	OSMO_ASSERT(dl_tbf->state_is(GPRS_RLCMAC_FLOW));